Serine Protease HTRA1 as a Novel Target Antigen in Primary Membranous Nephropathy
Serine Protease HTRA1 as a Novel Target Antigen in Primary Membranous Nephropathy
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DOI：
10.1681/asn.2020101395
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发表时间：
2021-07-01
影响因子：
13.6
通讯作者：
Beck, Laurence H.
中科院分区：
文献类型：
--
作者：
Al-Rabadi, Laith Farah;Caza, Tiffany;Beck, Laurence H.
靶抗原PLA 2 R、THSD 7A、NELL 1或Semaphorin-3B的鉴定可以解释大多数原发性膜性肾病（MN）病例。然而，在15%-20%的patient.Methods多管齐下的方法，使用传统和现代技术，聚集在一个新的靶抗原，并利用自身抗体滴度的时间变化的生物标志物发现的靶抗原仍然不明。免疫印迹的人肾小球蛋白质，然后由差分免疫沉淀和质谱分析的补充激光捕获显微切割，然后由质谱，洗脱免疫复合物从肾活检标本组织，和自身免疫分析的蛋白质片段microarray.Results这些方法确定丝氨酸蛋白酶HTRA 1作为一种新的足细胞抗原在一个子集的原发性MN患者。从两个病人的血清反应免疫印迹与肾小球提取物内的51 kD蛋白质和重组人HTRA 1，在还原和非还原条件下。这些患者的纵向血清样本似乎与临床疾病活动相关。与PLA 2 R和THSD 7A相关的MN一样，抗HTRA 1抗体主要是IgG 4，提示主要病因。在蛋白质片段微阵列上分析活动性疾病与缓解期间收集的血清，检测到活动性疾病中抗HTRA 1抗体的滴度显着较高。在三个队列中确定的14例患者中，在HTRA 1相关MN的免疫沉积物中特异性检测到HTRA 1。在大量MN活检标本中筛查118例“四阴性”（PLA 2 R-、THSD 7A-、NELL 1-、EXT 2-阴性）患者，发现其患病率为4.2%.Conclusions传统和更现代的技术融合鉴定丝氨酸蛋白酶HTRA 1为MN的靶抗原。
Background Identification of target antigens PLA2R, THSD7A, NELL1, or Semaphorin-3B can explain the majority of cases of primary membranous nephropathy (MN). However, target antigens remain unidentified in 15%-20% of patients.Methods A multipronged approach, using traditional and modern technologies, converged on a novel target antigen, and capitalized on the temporal variation in autoantibody titer for biomarker discovery. Immunoblotting of human glomerular proteins followed by differential immunoprecipitation and mass spectrometric analysis was complemented by laser-capture microdissection followed by mass spectrometry, elution of immune complexes from renal biopsy specimen tissue, and autoimmune profiling on a protein fragment microarray.Results These approaches identified serine protease HTRA1 as a novel podocyte antigen in a subset of patients with primary MN. Sera from two patients reacted by immunoblotting with a 51-kD protein within glomerular extract and with recombinant human HTRA1, under reducing and nonreducing conditions. Longitudinal serum samples from these patients seemed to correlate with clinical disease activity. As in PLA2R- and THSD7A- associated MN, anti-HTRA1 antibodies were predominantly IgG4, suggesting a primary etiology. Analysis of sera collected during active disease versus remission on protein fragment microarrays detected significantly higher titers of anti-HTRA1 antibody in active disease. HTRA1 was specifically detected within immune deposits of HTRA1-associated MN in 14 patients identified among three cohorts. Screening of 118 "quadruple-negative" (PLA2R-, THSD7A-, NELL1-, EXT2-negative) patients in a large repository of MN biopsy specimens revealed a prevalence of 4.2%.Conclusions Conventional and more modern techniques converged to identify serine protease HTRA1 as a target antigen in MN.